Soil Liquefaction Analysis of Banasree Residential Area, Dhaka Using Novoliq

Abstract

Liquefaction may occur when vibrations of an earthquake cause a soil to lose strength and flow like liquid. Dhaka City is almost flat, with many depressions, bounded by the Turag River in the west, the Tongi Khal in the north and the Burhiganga River in the south. The urban area is situated in a seismic zone, which has experienced earthquake intensities of up to IX at the Modified Mercalli scale. Many places under water are filled up by dragging sand for habilitation which is very much vulnerable for soil liquefaction. So, before every construction in liquefiable soil, liquefaction analysis of the soil layers should be done for the safety. The study attempted in performing liquefaction analysis by the use of software NovoLiq for assessing the potential possibility of liquefaction with respect to different characteristic parameters of soil conditions in Banasree, Bangladesh. At first the soil test report of different locations of Banasree were collected and from the soil test reports different input parameters were given in the software like soil depth, D50, PGA value, fineness content, SPT value according to different depth in the soil. From the analysis it was shown that in Banasree area the soil layers up to 55ft is liquefiable. So, soil layers up to 55 ft have to be improved if it is considered for any foundation purpose.